This invention relates to a pneumatic tire the weight of which is reduced by minimizing the thickness of the side walls thereof.
In recent years, great importance has been attached to the reduction of the weight of a vehicle which forms a part of the measure to improve the environment on the earth, and the reduction of the weight of a pneumatic tire as well has strongly been demanded. The construction of a pneumatic tire for passenger cars will now be discussed. As shown in FIG. 8, a ratio (SDH/SH) of the height SDH of a position W corresponding to a cross-sectionally widest portion of a tire to that SH of a cross section of the tire is about 0.5, and the thickness G (measurement between the outer surface of a carcass 1 and that of a side wall) of a side wall 2 is within the range of about 2.8-4.0 mm and uniform. Uniformly reducing the thickness G of the side wall 2 may be thought of as one of the methods of reducing the weight of such a pneumatic tire.
However, when a wheel having a tire the thickness G of the side walls 2 of which is reduced uniformly by not less than a certain level runs onto an edge stone, a side wall 2 becomes liable to be easily broken. Therefore, there is a limit to the reduction of the weight of the side walls.